Safety cover for electric switches



Oct. 27, 1925- D. HANE R FOR ELECTRIC SWITCHES SAFETY COVE Filed Sept. '7, 1923 FIG. 1

Patented Oct. 27, 1925.

UNITED STATES DAVID HANE, OF PITTSBURGH, PENNSYLVANIA.

SAFETY COVER FOR ELECTRIC SWITCHES.

Application med September 7, 1923. Serial No. 661,509.

To all whom t may concern.'

Be it known that I, DAvID HANE, a citizen of the United States, and resident of Pittsburgh, in the county of Allegheny and State of ennsylvania, have invented a new and usefull Improvement in Safety Covers for Electric Switches; and I do hereby 'declare the following to be a full, clear, and exact description thereof.-

My vinvention relates to electric switches including circuit breakers and other forms of heavy-duty circuit interrupters, and its object is to provide a. switch of this character with a safety cover which shall be substantially airtight and moisture-proof, and which, at the same time, shall not interfere with the normal operation of the moving switch parts.

My invention is concerned particularly,

' although not exclusively, with oil circuit breakers of the type including a group of stationary contact members arranged m rows of three or four such members, and co-operating with vertically vmovable contact members which are so suspended and loperated as to rise into engagement with the stationary contact members, and to descend away from the stationary contact members. In this type of circuit breaker, the fixed and movable' contact members are all suspended beneath a. supporting frame, and are enclosed in an oil tank for the purpose of suppressing arcs. The upper portions of the fixed contact members extend above the supporting frame and are provided with terminal connectors for attaching leadwires. These upper parts have heretofore been exposed to the air. When the exposed contact surfaces become moist it is possible for an arc to jump across between the adjacent conductors, and it is also possible for an operator to touch the exposed conductors when making repairs, or when inspecting the switch. Serious accidents and loss of life have frequently occurred in the operation of switches of this kind, and it is my specific object to protect such a switch by providing it with a safety cover which is so arranged as to exclude moisture and which at the same time, permits the operating levers fo-r the movable contact members to move freely in the usual manner.

To this end, I provide a closed box suitably molded from insulating material and having a cover o f special construction permitting the cover to be placed on the box without disturbing the lead-wires, and in such a way as to make close joints at the points where the lead wires pass through the top of the box. I also provide, at one side of the box, suitable openings to admit the switch-operating levers, and I mount upon the switch-operating levers a novel device which serves to close these openings in all positions of the operating levers.

' For a further understanding of my invention, reference may now be had to the accompanying drawing, in which Fig. l is a side view, partly in elevation and partly in section, showing an oil circuit breaker of a well-known type equipped with a safety cover constructed in accordance with my invention; Fig. 2 is a plan view of the safety cover; Fig. 3 is an enlarged fragmentary vertical section through a portion of the cover; Fig. 4 is an enlarged elevational view of the sealing plate which closes the lever openings; Fig. 5 is a perspective view of one of the cover slides; and Fig. 6 is a detail of the spring seat block between the switch arms.

In the vdrawing the numeral 2 indicates the usual frame of an oil circuit breaker, and the numeral 3 indicate the general construction of fixed contact members which are supported vertically in suitable seats in the frame 2, and which co-operate with movable contact members which are supported and guided for vertical movement beneath the fixed cont-act members by ordinary means, not shown. The movable contact members are suspended by means of hangers 4 from the inner ends of levers 5 which are arranged in pairs, as best shown in Fig. 2, and are mounted to rock upon a stationary pivot indicated at 6. The upper ends of the stationary contact members 8 are provided with suitable terminals 7 for attachment to the usual lead-wires 8. The details of construction of the switch members are not shown herein as these form no part in myinvention.

Below lthe frame is removably secured beneath the frame by `means of eye-bolts 10 that are pivoted to 2 the usual oil tank 9` the front of the tank 9 and extend between Thumb set screws 13 are also provided at the rear of the oil4 tank '9, and theselsetscrews extend through openings in the ranie 2 enel through Openings in luge lil carried by the tank 9. The construction of the oil tank 9 and its suspension mean-s are well known, and forni no part of my present invention, which is concerned withthe safety cover which rests upon the trarne 2 and encloses the parts of the switch which project above the franie2,

This safety cover consist-sof a vbox having Side Welle le, and having e @over Composed er me Seeteae 1.6 and 17. The Side Walle of the box l may suitably be molded in one piece from insulating material, or may be otherwise constructed, as desired. The'sections 16A and 17 of the ,boxcover lare arranged te ieil each ether apen a central line 1S, .Fia .2, and, en this line the sections et the eeveir are provided with sealfereuler Openings 19 WliQhimte te enclose the .leed- Wree Qi the. central row of switch Contacte. Tlie .eater rows ef leed-Wires 8a are ceived through similar divided openings, onehalf ,of each of these openings heilig' formed in the inaincever Section, while .the other half is formed in a block 'or slide 21 which .ie ,suitably mad-e from the Same meterial 'that ceinposing the box and cover. llieelielee 2l have side ribs 22 Wlieh rest in corresponding yseats orined in ,the box cover, 1S Shown in, Fig. 3. The outer ends of the Slides 2l are beveled es shawn et 23 to conlesiieasl JLe the .Shape ef the edges 2e Vof the main cover sections lef and 1'?, As shown a Figa ,l te 3, the edges Q f the cover See- V'tions are received in tapered seats 'formed in the upper edges of the Side walls 15- iter the box is placed uponthe switch, and the parts the cover Vare set in position, the tepef the bex may be covered with a .eeatf ine' of elastic ineulatngvmaterial so as te exelade air and. meist-ure! ln the reel' Wall 15 of the box, l provide vertical slots 26 ofproper width and spacins te reeeire the Switch levers 5,-' The vere tial slots 2.6 are so arranged as to permit the switch' levers 5to swing through their normal distese@ which maybe between the lull-lille neetien .enel tlle-detteellne Shown in lFig, 1, Carried by each pair of switch levers 5 and rest-ing against 'the inner surface et the reel' Wall l5. of the box, is e Sealills plete 27 suitably Composed of the Same meeriel es the bos' and cover, and lierl'la' Openings 28 wliel'l llt around the switch levers Greevee 29 may be formeel .n the plate 27 within each of the openings 2S and may be filled with felt 0.1 Similar material ,in-

Cleeted. et 30, vSe as te Vpredire@ a tight eine Vbetween the plete 27211161 the levers i The plete .27 .Carries a gasket 30W-f felt er other Suite-ble material 'Wlueli rests against the 'rear wall l5. o the bee, and 1s er sufeieat Size te eneleee the @ceilings ,in .lt-lie reel? '-W'all .fer all ,peeitlerls i-the le-verse, le

naaese order to press the plate 2T closely but slidably against the rear wall of the box, I provide between each pair of switch levers 5 a block 32, suitably of cast metal, having upper and lower flanges 33 that lit upon the upper and lower surfaces of the switch levers 5. The, blocks 32 are secured to the switch 'levers 5 by means of bolts 34 and carry seatsor tubes 35 which diverge toward the rear of the box and extend nearly to the sealing plate 27. Springs 36 are ca1.` ried by the sealing pla-te 2T and entend through the tubes 35 and into engagement with the blocksBQ, These springsare .of such sine and strength as to exert `c0115i'derable pressure uponthe plate 27 in -all posifr tionso this plate, thereby constantlyppressing the plate against the rear wall of the cover box. The spring tribes 35 may ybe loose on the springs 36, or hinged to the blocks 32, or maybe rigidly secured to the blocks 3Q. c

The lower edgesl of the walls l5 of the safety box are shaped to fit inthe freine@ of the switch. In 'the' switch shown4 on the` drawing, the fra-nie 2rhas`side langesfir which taper 'upwardly from front to rear, and the vside walls of the safety box are correspondingly tapered and are' curved lto lit the upper edges of the Hanges'i? as best shown in Fig. 3, Strips of felt, or the like, may e secured to the lower edges ofthe safety box to produce a close joint with the flanges 3'?. The lower cor-ners ,of the rear wall of the box are `cut away to lit the sido 'flanges 37' ,of the frame. The trent and rear walls of the box extend to the upper surface of the ltraine body, as shown 38 in Fig, 3, and may be provided on their lower edges with strips of feltor the like,

The eye-bolts' l() and the tl'luinb set screws 13 are employed for securing the safety box in place, and for this purpose the ,box is provided with biifuratfcd lugs 3,9 to rest upon the lugs 1l of the frame at the front of the box, kand with similar lugs L0 which 1,119,011 the frames at the rear of the box, adjacent to the usnal openings il through which the thumb Set screws 13 extend, i Suitable gaskets niay be placed between thc lugs ll and and beneatlithe luge 40- In applying the safety rover to the switch, the ySwitellflevers 5 are diseenneeled from lille hangers Lldlld are passed through the open ings 2G in the rear ot' the box and through the opening 28 in the plates 2'4", rlie blocks 232 and the springs 36 are then placed in position, the switch levers 5 are' attached to the hangers l and the belts ll0 and, the screws 13 are Secured in Place. The lead! Tires 8 are attached, te the terminals t el' the switch meinbers 3, and the sections 'of the, cover are then putA on the safetybox 3, thc eeetieael eensraeieli et' 'the coiffer enabling i 'eas -aiiel Slides. lt'ebefitted closely around the lead wires 8. The top coating of insulating material may be then a plied.

The safety box described above effectively excludes air and moisture from the parts of the switch which extend above the frame, but do not interfere in any way with the normal operation of the switch.

It will be understod that the principles of my invention may be employed in constructing safety covers for switches of many different types, and that the details of construction herein shown may be varied in many respects without departing from my invention as set forth in the appended claims.

l claim as my invention:

l. The combination with an electric switch box provided with a plurality of terminals and conductors leading therefrom, of a safety box comprising a casing having side walls adapted to be engaged and be closed by said switch box, and with a re-v movable cover made in two sections having openings formed at their meeting edges for some of said conductors, and also having openings adjacent to their outer edges, and slides for closing said last-named openings, the said slides and the adjacent portions of said cover sections also being formed with conductor receiving openings.

2. The combination with an electric switch provided with a switch box and a cover plate therefor, for supporting a plurality of terminals and conductors leading therefrom, of a safety box comprising a casing having side walls adapted to engage and be closed by said cover plate, and having a removable cover made in two sections with a row of conductor receiving openings formed at their meeting edges.

3. A safety cover for electric switches comprising a box having a vertical guide slot in one of its walls to admit a switch operating lever, a sealing plate having an opening to admit said lever and adapted to close said opening in all positions of said lever, and resilient means interposed between said lever and said plate for constantly pressing `said sealing plate against said wall.

4. A safety cover for electric switches comprising a box having a vertical slot in one of lits walls to admit a switch operating lever, a sealing plate resting slidably against said wall adjacent to said slide, an endless gasket carried by said plate and adapted to surround said slide in all positions of said lever, an opening formed in the said plate to admit the said lever, sealing means surrounding said lastnamed opening, and springs adapted to be carried by said lever for pressing said plate against the wall of said box in all positions of said lever.

5. A safety cover for electric switches comprising a box having a pair of vertical slots formed in one of its walls to admit switch-operating levers, a block adapted to be mounted between the said levers, a sealing plate resting slidably against the said wall, an endless gasket carried by said plate and adapted to close said openings in all positions of said plate, openings formed in the said plate to receive the said levers, sealing means surrounding the said openings, and springs extending between the said block and the said plate and acting to press the said plate against said wall in all positions of said plate and said levers.

6. A safety cover for electric switches comprising a four-sided box having an open lower side and having its lower edge shaped to conform to a switch frame, said box having a sectional cover provided with leadwire receiving openings at its meeting edges, and also provided with other openings for admitting lead-wires, slides for closing the said last-named openings, said slides and the adjacent portions of said cover sections being provided with lead-iwire receiving openings, a pair of vertical slots formed in one wall of said box to admit switch operating levers, a block adapted to be carried between said levers, a sealing plate resting slidably against the wall of said box, an end# less gasket carried by said sealing plate and surrounding said slots in all positions of said plate, openings formed in said sealing plate to admit the said switch levers, sealing means surrounding each of said openings, and spring extending between said block and said plate and tending to force said plate against the wall of said box.

7. The combination with an electric switch box provided with a plurality of terminals and conductors leading therefrom, of a switch box comprising a casing having one side removable and formed of sections which have openings formed at their meeting edges to admit conductors, and provided in one of its walls with an opening through which an operating lever may pass, a shiftable plate covering said opening, and adapted to surround the operating lever, and means for yieldingly holding said plate in engagement with the last mentioned wall.

8. rlhe combination with a switch frame and terminals carried thereby, of cover structure for said terminals, comprising a lower casing member below said frame, an upper casing member, a single means for clamping the casing members in fixed relation to said frame, the upper casing member being provided with separable cover plates, each having semicircular openings that cooperate with similar openings in the otherl to accommodate conductors leading to said terminals.

In testimony whereof I, the said DAVID HANE, have hereunto set my hand.

DAVID HANE. 

